This repository contains a set of programming puzzles that are solved using Kotlin language (hints, solutions tests and useful links are here as well). Purpose of this repository is to help you to practice and develop strong problem-solving skills. This will help you to become better programmer and improve you chance of getting new job, by passing whiteboard coding interview.

Each puzzle is located in separate package and it contains of 3 files (screen):

• Puzzle.md - description of the task.
• Puzzle.kt - empty method/class where puzzle should be solved. This file also contains a set of JUnit tests.
• PuzzleSolution.kt - file that contains solutions.

Keep in mind that each puzzle will usually have more than one solution. Even simple puzzle like String reversal can be solved in 10 different ways. Usually, we compare various solutions using (Big O notation) to determine space/time complexity and we look at code readability.

1. Checkout the and open the project
2. Solve puzzle
3. Run the tests

Puzzles below are segregated by different difficulty. If you want to solve puzzles by problem type, please check this section.

Some puzzle may contain a reference to other puzzles that should be solved before to have better understanding of the problem. To succeed you need to practice often, repeat same puzzles multiple times and be persistent over time. Take your time before you take a look at the presented solution. Good luck!

New in Town

• Capitalize sentence
• Range contains range?
• Add up to
• Linear search
• Count down
• Count up and down
• Generate all pairs
• List count unique values
• Print number
• Print number with steps
• Power
• Factorial
• Product
• Capitalize first
• Decapitalize const
• Longest word

Apprentice

• Is palindrome
• Is tolerant palindrome
• Is anagram
• Max occurring char
• String reversal
• Find the vowels
• Int reversal
• Pyramid generator
• Steps generator
• Fizz Buzz
• Caesar Cipher
• Repeated Character

Warrior

• Spiral matrix generator
• Int queue
• Generic queue
• Combine two queues
• Two stack queue
• Int stack
• Generic stack
• Bubble sort
• Selection sort
• Square equals
• Sum zero
• Digit frequency
• Get duplicated arguments
• Find pair with target average
• Tree traversal
• Tree level width
• Binary search tree (insert)
• Binary search tree (validate)
• Any callback
• Flatten
• Binary search
• Surrounded letter
• Insertion sort

Commander

• List chunking
• Linked list
• Linked list midpointu
• Circular check
• Linked list take n-th element from last
• Is sub string
• Merge sort
• Fibonacci
• Fibonacci with recursive cache
• Max sub list sum
• Min sub list length
• Subtract

• GeeksForGeeks - large and nicely segregated set of problems.
• HackerRank - large set of problems and additional interview problems for business.
• Project euler - more complex challenges, usually related to mathematics. Site already contains 600+ problems and a new code challenge is available very week or two. You will probably have to discuss problem with community because solutions are not on the website.
• Advent of code - one month of various programing problems released daily at the end of the year. Fortunately archive of past events is still there.
• Code Google Com Codejam - Google Code Jam, calls on programmers around the world to solve challenging, algorithmic puzzles against the clock. They publish all the past problems on their website.
• CoderByte - 200+ challenges, data structures / algorithms / company interview problems segregated by difficulty. Unfortunately most of them is only available for premium users. Premium gives you access to premium step-by-step solutions and user solutions.
• CodeChef - contains set of programming problems segregated by difficulty.
• LeetCode - data structures / algorithms / company interview problems segregated by difficulty.
• Code Forces - list of programming puzzles is smaller than other websites, but you will still have plenty problems to solve.
• Spoj - list of programming puzzles is smaller than other websites, but you will still have plenty problems to solve.

• JavaScript Algorithms and Data Structures Masterclass
• The Coding Interview Bootcamp Algorithms + Data Structures
• Master the Coding Interview Data Structures + Algorithms
• Learning Algorithms in JavaScript from Scratch
• Data Structures and Algorithms Deep Dive Using Java

• Cracking the Coding Interview, 6th Edition
• Algorithms, 4th Edition
• Introduction to Algorithms, 3rd Edition (The MIT Press)
• More books...

• VisuAlgo - visualizes data structures and algorithms through animations algorithms.
• Data structures explained - description of various data structures.
• Big-O Cheat Sheet - algorithms nad data structure operations complexity cheat sheet.
• Sorting algorithms animations - visually compares most popular sorting algorithms using animations.

• Coding Interview University
• Awesome Interview Questions
• Google Interview University
• Interviews

If you think something is sdfds sdf ds fsd fds fds fds fds ds dsincorrect, have a better solution, give feedback or simply you want to add new coding puzzle just create PR or open a new issue.

• Alan Evans
• Norbert Kiesel
• David Mozano
• Yannis Barbakadze

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